Interventions for health workforce retention in rural and remote areas: a systematic review

Background Attracting and retaining sufficient health workers to provide adequate services for residents of rural and remote areas has global significance. High income countries (HICs) face challenges in staffing rural areas, which are often perceived by health workers as less attractive workplaces. The objective of this review was to examine the quantifiable associations between interventions to retain health workers in rural and remote areas of HICs, and workforce retention. Methods The review considers studies of rural or remote health workers in HICs where participants have experienced interventions, support measures or incentive programs intended to increase retention. Experimental, quasi-experimental and observational study designs including cohort, case–control, cross-sectional and case series studies published since 2010 were eligible for inclusion. The Joanna Briggs Institute methodology for reviews of risk and aetiology was used. Databases searched included MEDLINE (OVID), CINAHL (EBSCO), Embase, Web of Science and Informit. Results Of 2649 identified articles, 34 were included, with a total of 58,188 participants. All study designs were observational, limiting certainty of findings. Evidence relating to the retention of non-medical health professionals was scant. There is growing evidence that preferential selection of students who grew up in a rural area is associated with increased rural retention. Undertaking substantial lengths of rural training during basic university training or during post-graduate training were each associated with higher rural retention, as was supporting existing rural health professionals to extend their skills or upgrade their qualifications. Regulatory interventions requiring return-of-service (ROS) in a rural area in exchange for visa waivers, access to professional licenses or provider numbers were associated with comparatively low rural retention, especially once the ROS period was complete. Rural retention was higher if ROS was in exchange for loan repayments. Conclusion Educational interventions such as preferential selection of rural students and distributed training in rural areas are associated with increased rural retention of health professionals. Strongly coercive interventions are associated with comparatively lower rural retention than interventions that involve less coercion. Policy makers seeking rural retention in the medium and longer term would be prudent to strengthen rural training pathways and limit the use of strongly coercive interventions. Supplementary Information The online version contains supplementary material available at 10.1186/s12960-021-00643-7.

the development of strong professional relationships between health providers and patients which are vital for improving health outcomes of vulnerable populations [2,3].
Rural and remote populations, however delineated, even in high-income countries (HICs) such as Australia, USA and Canada [4][5][6], have a range of health vulnerabilities and frequently experience substantial disparities in health outcomes due to socio-economic factors, increased health risk factors and poorer access to health care compared to metropolitan populations [4,7]. A high proportion of Indigenous peoples live in remote and rural areas, and they experience considerably poorer health outcomes than non-Indigenous citizens [8]. Recent health care system performance rankings for Australia, Canada and USA reveal poor access (4th, 10th and 11th respectively out of 11 countries) and equity rankings (7th, 9th and 11th respectively) [9]. Improved retention of health professionals in non-metropolitan areas would have lasting positive impacts on the health and wellbeing of rural and Indigenous populations.
Prior reviews suggested that health professional education delivered in rural areas is positively associated with rural retention, although participating in rural training may reflect pre-existing intention and motivation for rural practice rather than the intervention itself increasing rural retention [10,11]. Many of the positive and negative intrinsic and extrinsic motivators are either personal or professional support factors which may be modifiable [12]. Despite this, and the World Health Organization (WHO) recommending a number of personal and professional support interventions to increase retention, there is a lack of evidence of their effectiveness and cost-effectiveness [13]. While coercive regulatory interventions, including financial incentives with return-of-service (ROS) requirements, are effective short-term recruitment strategies, there is little evidence of their long-term positive impact on rural or remote health workforce retention [14][15][16]. Financial retention incentives for individuals without ROS requirements are prevalent. WHO recommends offering increased allowances, grants for housing, increased paid recreational leave, and assistance with transport [13]. However, the evidence from HICs about the effectiveness of financial incentives (with no ROS obligation) is lacking.
Given these significant gaps in our understanding, this review aims to update existing evidence [17] by examining associations between interventions designed to retain health workers in rural and remote areas of HICs and quantifiable workforce retention outcomes.

Methods
To ensure that no other research group had already undertaken the work, scoping of existing retention reviews included a preliminary search of PROSPERO, MEDLINE, the Cochrane Database of Systematic Reviews and JBI Evidence Synthesis. Four review papers were found that either needed updating or had a much narrower scope than this review [1,[17][18][19].
This systematic review accords with the Joanna Briggs Institute (JBI) methods for systematic reviews of aetiology and risk evidence [20] and followed an a priori published protocol which more fully describes methods and definitions [21]. However, studies reporting job satisfaction without direct turnover or retention outcomes were excluded [22], and we did not use the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach for grading the certainty of evidence.

Inclusion criteria
Inclusion and exclusion criteria are summarised in Table 1. Studies were confined to 2010 or later because of available substantive reviews that synthesised the evidence relating to retention up to that time [1,11].

Search strategy
A three-step search strategy was used to locate both published and unpublished studies [21]. The searches were undertaken 11-12 April 2019 and repeated on 1 July 2020 to capture any additional published studies. MED-LINE (OVID), CINAHL (EBSCO), Embase, Web of Science, Scopus, and Informit databases were searched as were ProQuest Dissertations and Theses, Trove and MedNar and the websites of government and peak nongovernment organizations. The MEDLINE search strategy is available as an Additional file 1.

Study selection
All identified citations were collated and uploaded into EndNote Version X9 (Clarivate Analytics, PA, USA) and duplicates removed. Titles and abstracts were screened by two independent reviewers against the inclusion criteria. Potentially relevant studies were retrieved in full and their citation details were imported into the Joanna Briggs Institute's System for the Unified Management, Assessment and Review of Information (JBI SUMARI; JBI Adelaide, Australia). Using the inclusion criteria, the full text of each citation was assessed independently by two independent reviewers. In the few instances where more than one paper was from the same research study only one paper was included. Reasons for exclusion of full text studies were recorded and are reported in the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) flow diagram ( Fig. 1) [24].

Assessment of methodological quality
Eligible studies were critically appraised and scored by two independent reviewers for methodological quality using the appropriate JBI critical appraisal instrument [25]. Disagreements were resolved through discussion, or with a third reviewer.

Data extraction
Data were extracted by two independent reviewers using the standardized data extraction tool from JBI-SUMARI. Study citation details, study objective, participant information, details of the setting/context, details of the retention intervention, and study results for the relevant outcomes were extracted.

Data synthesis
The structure of the narrative synthesis of extracted data was based on categories for rural health workforce interventions used in the WHO Global Policy Recommendations [26]: education; regulatory interventions; financial incentives; and personal and professional support. A further category-health systems-was added, as proposed by Putri et al. [27].

Study selection
The search strategy identified 2592 papers, with a further 57 papers identified from other sources (Fig. 1).
After duplicates were removed 2043 papers remained. 1901 papers were excluded by title and abstract screening and 142 articles underwent full text assessment. 108 were excluded, leaving 34 articles. The main reasons for exclusion on full text review were a lack of quantifiable retention outcome measures, no intervention or ineligible study type (Additional file 2).

Methodological quality
Most were cohort studies (29/34, 85%). Methodological quality of included studies was generally low (Additional file 3). The median score for included cohort studies was 16 out of a maximum of 22 (interquartile range [13][14][15][16][17][18][19][20]. Only one-third of included studies applied appropriate statistical analysis, with less than half adjusting for key potential confounders. Many studies had no comparator group.

Findings
A meta-analysis could not be conducted because the studies were highly heterogeneous, reporting different interventions and retention outcomes. Hence, a narrative approach was taken.

Education
Twenty-one studies investigated the impact of educational interventions, including: selecting university students with rural backgrounds [31,32,38,58,60]; location of university training and its duration (rural, within a             Simulated loan forgiveness programs (representing an almost doubling of income for rural physicians) was associated with a small (up to 3%) decrease in the probability of them moving away from the same rural area after 1 or 2 years of service, while a 5% increase in rural county physician salary decreased the probability of moving away from the same rural area after 2 years by 7%. There was a decreasing marginal return on the probability of moving away from the same rural area with salary increases of 10 and 20%.
A 5% increase in mid-level practitioners in rural counties increased the probability of rural physicians moving away after 2 years by 8%, while a 5% increase in RNs in rural counties decreased the likelihood of physicians leaving rural areas by 3%. Medicaid and Medicare expansion in rural areas were associated with increased physician movement away from their rural county of service after 2 years by 10% and 11% respectively jurisdiction, within the same country) [31,32,36,38,43,48,54,56,58,60]; multi-faceted interventions providing support for advancing education to a degree level (paid tuition with ROS obligation, scheduling flexibility, locally accessible, academic support locally; off-campus, decentralised education opportunities) [28][29][30]; location of postgraduate training [44-47, 52, 53, 58, 59]; and multifaceted interventions supporting skills training for fully qualified rural health professionals (backfill, payment for supervisors) [42]. One study measured retention intentions; the remainder measured actual retention or turnover outcomes [32]. Selecting university students from rural backgrounds was consistently associated with increased rural retention [31,32,38,58,60]. Undertaking 1 or more years of university health training in non-metropolitan regions was associated with longer retention [43,48,54,56,60]. The retention of students who chose longer duration of rural training exposure during their basic training (2 years) were approximately double (odds ratio 5.38, 95% CI 3.15-9.20) those of students who chose 1 year (odds ratio 2.85, 95% CI 1.77-4.58) [38]. Opting in to a much shorter 1-month rural clinical placement during final year as a dental student was associated with increased prevalence of working rurally as a dentist in both 2015 and 2017 (prevalence ratio 1.93, 95% CI 1.19-3.15) compared to those who had no rural clinical placement [31]. Undertaking basic health professional training at an international versus a domestic university had no association with rural retention of graduates in two studies [36,48]. One study showed internationally trained doctors were more likely to leave the province than graduates trained within that province [48].
Three studies with 392 nurses [28][29][30] showed that supporting existing employees of rural health services and rural residents to undertake further university study using distributed models of education in conjunction with paid tuition, flexible schedules which allowed concurrent part-time or full-time paid employment, local teaching and tailored academic support was associated with high retention or low turnover and vacancy rates. Annual turnover of Licensed Practice Nurses at a US rural medical centre decreased from 16.8 to 6.8% following program implementation [28]. Nilsen reported 4-year nurse retention of 92.5% in a northern Norwegian county in an off-campus rural training group, compared to 70% for those who trained on-campus [29].
Nine studies investigated associations between retention and rural or remote location of postgraduate training. Two studies, specifically examining internship location and retention [41,54], showed there was considerable variation in the proportion of postgraduates retained in rural or remote locations (ranging from approximately 0.35 up to 0.8). Undertaking postgraduate training in smaller rural sites (population < 10,000) was associated with marked increase in retention (odds ratio 36, 95% CI 12-109) [53]. A positive association between rural or remote postgraduate training and retention was reported to be stronger amongst rural origin registrars [58]. One Canadian study found that postgraduate (residency) training in a largely rural province was not a significant predictor of retention in the province, after adjusting for undergraduate training in that province [48]. An Australian study found an association between postgraduate rural generalist training (training which includes developing advanced skills, for example in Aboriginal health) and remote retention [54].
A small study of a skills enrichment program for fully qualified rural physicians, with provision for backfill and funding for preceptors for up to 1 year, reported all 29 were retained 5 years later, whereas significantly fewer matched physicians (22/29) not participating in the program were retained (risk ratio 1.3 95% CI 1.1-1.6) [42].

Regulatory interventions
Nine studies examined the effectiveness of regulatory interventions on retention of doctors. One study simulated the impact of different types of health workers on doctor turnover. Increasing access to mid-level practitioners such as Physician Assistants and Advanced Nurse Practitioners was associated with a significantly increased probability of physicians moving away from the area after 1 or 2 years of service as these providers are a substitute for physicians [34]. In contrast, increasing rural supply of registered nurses, who provide services that complement those of physicians, was associated with a significant decrease in the likelihood of rural physicians leaving [34].
Eight studies investigated interventions which required service in rural areas (for a varying length of time) in return for a benefit. Several studies demonstrated that interventions comprising ROS in a rural area in exchange for highly valued visa waivers or access to professional licenses or provider numbers were associated with comparatively low rural retention/high turnover, especially once the ROS period was complete. Visa waiver recipients in Nebraska, USA, were almost four times more likely to leave rural areas of the state than state loan repayment recipients [51]. In contrast, the loan repayment recipients remained in rural areas for many years, with more than half still there 17 years later. Half of the visa waiver recipients left within 2 years of completing the 3-year minimum obligatory period. A study of loan repayment recipients who had completed ROS obligations in Colorado, USA, found that approximately twothirds of rural recipients were still practising in a rural community compared to almost 100% of urban recipients who were still practising in an urban community [33]. Almost half (n = 10/21) of the loan repayment recipients who had finished their rural service obligations stayed less than 1 year beyond their ROS obligation [33]. One study found that international medical graduates (IMGs) who had yet to complete their ROS obligations had a substantially higher hazard of turnover than IMGs without locational restrictions [37]. Another study, however, found no statistically significant difference in the risk of leaving rural for IMGs, whether they had work location restrictions or not, compared to non-restricted graduates [36].
The intervention groups in two studies were subject to different types of regulatory interventions [50,60]. Playford et al. were unable to differentiate the association of retention with two different interventions: Bonded Medical Places (access to a government subsidised university place) and Medical Rural Bonded Scholarships (scholarships paid to students during university training), [60]. Mathews et al. similarly did not differentiate between fellowships (funding provided to postgraduates training in a particular speciality), a bursaries program (scholarship to university students), and another program which provided special access to a postgraduate training place [50]. Hence it is not possible to determine which particular intervention(s) may have been associated with rural retention in these studies.

Financial incentives
Five studies investigated associations between retention or turnover and various financial incentives, including having guaranteed access to paid locums [57], subsidized school fees for children [57], receiving retention incentive payments [35,57], rural skills loading [57], increasing the salary of rural health professionals [34], reduced costs of malpractice insurance [61], and receiving Rural Doctors' Association Settlement Package payments as a New South Wales (NSW) Visiting Medical Officer [37]. All studies involved doctors and took some account of potential confounders. One study was a simulation, another a discrete choice experiments and a further study recorded retention intentions [34,57,61]. Only two Australian studies entailed observed retention or turnover behaviour [35,37].
Both a 50% increase in retention payments (β coefficient 1.423, p < 0.001) and 20% rural skills loadings (β coefficient 0.363, p < 0.001) were associated with increased probability of retaining General Practitioners (GPs), but were not as effective as providing guaranteed paid locum relief for 6 weeks every 12 months (β coefficient 1.624, p < 0.001) [57]. While locum relief incentives were important for retention of all rural GPs, regardless of location or on-call frequency, rural skills loadings were most important for GPs also doing hospital work. GPs with dependent children were also more responsive than GPs without dependent children to subsidised school fees [57]. Australian Government Rural Incentive Program payments were more effective in recruiting new GPs to incentivised rural areas rather than increasing the retention of existing GPs [35]. GP workforce retention was also significantly negatively associated with geographical remoteness in NSW, Australia, where GP retention incentives are scaled according to remoteness [37]. NSW GPs who were Visiting Medical Officers (and thereby received payments according to the Rural Doctors' Association Settlement Package), had a 50% lower risk of leaving rural communities compared to GPs who were not [37]. In the USA, a 5% increase in rural county physician salary, simulated as an increase in reimbursement rate, was found to significantly decrease the probability of moving away from the same rural area; male physicians were more receptive to a policy change in reimbursement than their female counterparts [34]. Pepper et al. found that financial disincentives, in the form of high malpractice insurance rates, were associated with physicians planning to move their practice out of the (largely rural) state of Wyoming, rather than remaining in the state [61].

Personal and professional support
Four studies examined the effectiveness of personal or professional support interventions on actual retention or turnover of rural health professionals [39][40][41]55]. None adjusted for potential confounders. Offering medical students early sign-up to internships in a specific rural region, rather than going into a lottery for the opportunity to choose their preferred internship location, was associated with double the proportion of interns still working as physicians in the study area (29% versus 15%) [41]. However, retention of early sign-up interns was entirely in the most densely populated municipalities and none were recruited to any of the 15 remote municipalities. In a study of a cognitive behavioural coaching program (advertised as a work-life balance retreat), 94% of rural GPs who voluntarily attended were subsequently retained in rural general practice compared with 80% of the general rural doctor population (p = 0.027), despite their higher intention to leave rural general practice before coaching [40]. One study of an enhanced professional support network for rural surgeons added little to the extant literature as it lacked a comparator [39] and another low quality study reported that approximately two-thirds of survey respondents to a rural medical practice survey indicated that more reasonable hours of work, availability of locum tenens, availability of professional backup and educational opportunities for children would influence their retention intentions [55].

Health systems
One USA study, where there is no universal health care insurance, used simulation to examine how expansion of publicly funded access to health care for some segments of the population (age 65 or older or younger but with disabilities-Medicare; low income-Medicaid) was associated with physician turnover [34]. Expansion of Medicaid and Medicare in rural areas was found to increase likelihood that physicians moved away from the rural county they worked in and became clinically inactive [34].

Discussion
This review updates our understanding of the effectiveness of interventions to retain health workers in rural and remote areas. In contrast to a 2010 review which found little evidence of the effectiveness of any specific retention intervention except for regulatory interventions requiring ROS [17], this synthesis of evidence from 34 recent studies provides strong evidence about the effectiveness of educational interventions. Specifically, this review shows that a range of educational training pathway factors have strong associations with subsequent rural retention. These findings are consistent with other studies of associations between various rural pathway factors (not necessarily of interventions) and rural workforce supply (which reflect both recruitment and retention) [62,63]. Policy makers can be confident that selecting rural (or remote) background students and training them in rural (or remote) areas, with the specific intention of preparing them for rural or remote practice, contributes to future rural retention.
Despite evidence from Northern Territory, Australia that Indigenous practitioners may have longer retention and lower turnover in remote communities [64], no study examined the effectiveness of selecting Indigenous students (or students from disadvantaged backgrounds) on subsequent retention in rural and remote Indigenous communities. The contribution of different elements of rural training programs to rural retention, such as the relative importance of mentorship by rural health professionals, rural career counselling and support and strong institutional social accountability mandates also remains unclear. Thus, associations between different elements of rural education pathways and retention remain largely untested and poorly understood.
Interventions requiring rural service in exchange for visa waivers or access to professional licenses or provider numbers were associated with comparatively low rural retention, especially once the ROS period was completed.
Retention did, however, vary depending on the benefit accepted in exchange for rural service: health professionals choosing loan repayments tended to be more likely to stay following completion of ROS than health professionals accepting visa waivers, perhaps because recipients had greater choice in whether to enrol in the program than recipients seeking visa waivers. These findings were consistent with earlier US studies [65][66][67][68]. Current evidence therefore suggests that rural ROS programs which are strongly coercive should be used prudently if a primary aim of the program includes improved rural retention.
Evidence about the impact of financial incentives (with no ROS requirement) was limited because of the small number of studies and failure to quantify actual retention behaviour of health professionals. Perhaps the strongest evidence suggests that blanket financial retention incentives for rural GPs in Australia were ineffective [35]. This may partially be explained by the findings of another study which reported that many rural health professionals are not influenced by incentives of any type to stay, suggesting that any financial incentives should be tightly targeted only to those rural health professionals whose decisions about practice location are influenced by monetary incentives [57].
Despite these findings, the evidence-base could be stronger. The methodological quality of the studies was generally low. Only one-third of the studies were assessed as applying appropriate statistical analyses. Many studies lacked comparator groups or failed to account for potential confounders; others only provided a descriptive analysis. A further limitation was the heterogeneity of both interventions and study outcome measures, precluding a meta-analysis. All included studies were observational in design and thus subject to various types of bias-particularly selection bias-and unable to prove causality of associations. Definitions of rural and remote were not consistent between studies but were at the authors' discretion. There was also an absence of cost-effectiveness studies. The systematic review method used also has its limitations, most especially its focus on what interventions work, without explicitly adequately investigating the contexts and mechanisms by which interventions are effective. This could be the subject of future research.
Most studies examined interventions for retaining doctors, with very few studies of nurses, Indigenous health practitioners or allied health professionals, thereby limiting the generalisability of the evidence to other health professions. Thus, despite the importance of comprehensive primary health care to improving the health outcomes for rural and remote populations, evidence on how best to retain nurses, Indigenous health practitioners and allied health professionals remains scant. This gap in the evidence, together with very few studies of retention in remote areas, may have a disproportionately negative impact on policy making in remote areas which frequently rely heavily on nurses, nurse practitioners and Indigenous health practitioners for primary health care service provision and where retention of health professionals can be extremely problematic [69].

Conclusion
There is a growing body of evidence about the effectiveness of interventions to improve the retention of rural health professionals. The best available evidence suggests that policy makers can be confident that selecting health professional students based on rural background, encouraging distributed training based in rural and remote areas during their basic and subsequent training and removing barriers to rural health professionals for further developing their skills (both professional and personal) and qualifications is associated with longer rural retention.
However, there remain significant gaps in our knowledge and a stronger evidence base is required. Future research should seek to address methodological limitations, such as the lack of experimental studies and heterogeneity of retention outcome measures. The scope of future rural retention intervention studies should extend to include the retention of nurses, allied health professionals and Indigenous health practitioners, particularly in remote areas. These will lend greater confidence to policy makers to be able to justify and expand their armamentarium of potential interventions to improve retention and defray the high human and financial costs of rapid workforce turnover.